There was a lot of talk about this following the Fed Ex crash at NRT and a number of theories were expounded:

1. The structure of the wing was such that the MLG didn't gave way in case of a very heavy landing, which meant it was more likely to flip over.

2. The tail section is considerably smaller than that of the DC10, which apparently led to control difficulties.

3. The wingspan (at less than 50m) is considerably shorter than that of the A330/340 and 777, which cut its range considerably.

4. It has the reputation among crews of being a handful; there was very detailed discussion of the techniques and the importance of being stabilised early in the approach and how easily an MD11 could "get ahead of" an unprepared or inexperienced pilot, with potentially catastrophic results.

Quoting kaitak (Reply 1):2. The tail section is considerably smaller than that of the DC10, which apparently led to control difficulties.

I think this factor alone probably contribues to the recent rash of MD-11 freighter landing accidents the most...The MD-11 is known to be most unforgiving of sloppy handling and poor airmanship during the landing phase of flight. Although in the NRTFX accident, the preliminary report seems to show that the flight crew put in *WAY* too much ailieron input, with predictable results

Quoting kaitak (Reply 1):1. The structure of the wing was such that the MLG didn't gave way in case of a very heavy landing, which meant it was more likely to flip over.

This seems to be what turned damaging hard landings into disastrous flip/fire situations.

As I understand it, the main gear is not offset from the wing spar, but directly under it. So in a very hard landing situation, instead of the gear just punching through the wing (as it did on BA038, for example), the spar breaks and one wing separates from the aircraft, causing the aircraft to flip.

Compounding this problem is that the control characteristics of the MD-11 make extremely hard landings more likely, especially at freighter landing weights.

It's definitely responsible for the twitchy handling on landing, which can lead to hard landings... but those hard landings would probably be just that in any other airplane. In the MD-11, hard landings often break the MLG, which in turn flips the plane over. Now you have a serious accident out of what would have been a relatively minor incident in another airplane.

It has happened too many times, not just to freighters either but to passenger MD-11's too (there was one famous one somewhere in Asia, where the plane flipped on landing but miraculously only something like 3 people out of 250 or so died).

The MD-11 has a series of design quirks that make it more prone to this kind of accident than other planes. It's not just the stabilizer.

btw I'm sure this thread, like all the others about the MD-11, will get its share of people claiming there's nothing wrong with the MD-11... but I just think there's too much evidence the other way to really believe that anymore.

I'm tired of being a wanna-be league bowler. I wanna be a league bowler!

There are two fundamental elements of the MD-11 design that have led to its less than stellar record. The first is the landing gear/wingspar design, which, as seabosdca said, does not allow the landing gear to break off cleanly, but instead acts like a fulcrum over which the wing spar breaks. As far as I know only the DC-10 and MD-11 have this design; but the DC-10 has better low speed handling and hence has never done it (unless it happened on UA-232). The second is that MD tried to improve the drag by employing "relaxed stability", i.e. a more aft CG than any other airliner with the goal of reducing drag. They did succeed in reducing drag (hence the smaller stabilizer) but the result is the handling quirks, especially during landing.

The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler

Ugh!! I was waiting for another MD-11 thread to start. This topic has been beaten to death on this forum many times over. Please do a search before we rehash it all over again.

In my opinion there is nothing extremely unsafe about the type or it would have been forced to undergo massive mandatory modifications of have been grounded by now. Yes, there is no denying that it is a handful to fly as we have all read, but so are some other aircraft types and all that demands is greater training and awareness of these particular traits. The aircraft has been in-service for nearly 20 years and many operators have had no incidents whatsoever.

I am probably in the minority here in my defense of the type as there is a pretty vocal anti-MD-11 a.net group on here that will pounce on this thread for sure.

Quoting kaitak (Reply 1):1. The structure of the wing was such that the MLG didn't gave way in case of a very heavy landing, which meant it was more likely to flip over.

Of all the "theories" or reasons that are still continually perpetuated, this one is the silliest. Any aircraft that touches down on one MLG truck at a high rate of speed beyond its design limits will most-likely cause the wing to detach. Also, here is nothing inherently different with the MD-11's wing and landing gear design and configuration than the DC-10 which does not have this supposed "problem".

35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.

Quoting TZTriStar500 (Reply 6):Of all the "theories" or reasons that are still continually perpetuated, this one is the silliest. Any aircraft that touches down on one MLG truck at a high rate of speed beyond its design limits will most-likely cause the wing to detach. Also, here is nothing inherently different with the MD-11's wing and landing gear design and configuration than the DC-10 which does not have this supposed "problem".

BA and SV have had incidents with 777s where exactly this situation happened and the wing did not detach; instead, the gear punched through the wing.

Also, it's at least conceivable that this problem is what caused UA 232, the Sioux City DC-10, to flip over.

If hard landings consistently broke wings off on all airliners, we'd see many more flips on landing with other types.

Quoting TZTriStar500 (Reply 6):Yes, there is no denying that it is a handful to fly as we have all read, but so are some other aircraft types and all that demands is greater training and awareness of these particular traits.

No other medium to large airliner introduced in the last 30 years has anything like the MD-11's reputation for poor handling, or its record of landing accidents. I think a belief that MD pushed the design envelope too far with the small wing and stabilizers is easily justified by the facts. That doesn't mean every MD-11 flight is doomed to catastrophe, or that the aircraft should be grounded.

Still, I will breathe a sigh of relief when the last MD-11 passenger flight touches down safely, and another one when the last example of the type is retired.

Quoting SEPilot (Reply 5):The first is the landing gear/wingspar design, which, as seabosdca said, does not allow the landing gear to break off cleanly, but instead acts like a fulcrum over which the wing spar breaks. As far as I know only the DC-10 and MD-11 have this design; but the DC-10 has better low speed handling and hence has never done it (unless it happened on UA-232).

I don't know where you get this from because you keep stating it like its fact. The DC-10/MD-11 gear is mounted aft of the rear spar just like the majority of all airliner designs. There is nothing inherently different about its design. All conventional MLG designs have the forward attachment to the rear spar and the aft to a MLG beam or aux spar. As seen in the images of the 757, 737NG, 767, and DC-10, I defy you to tell me where is the "flaw" or that Douglas did anything vastly different than convention.

757

737NG

767

DC-10

35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.

Quoting seabosdca (Reply 7):BA and SV have had incidents with 777s where exactly this situation happened and the wing did not detach; instead, the gear punched through the wing.

Also, it's at least conceivable that this problem is what caused UA 232, the Sioux City DC-10, to flip over.

If hard landings consistently broke wings off on all airliners, we'd see many more flips on landing with other types.

Thanks for the lesson on aircraft design from a lawyer. Gear isn't designed to "punch" through the wing either.

I wasn't talking about hard landings. I specifically stated high rates of speed beyond the certificated flight envelope which is entirely different. An aircraft isn't designed to handle all extreme loading conditions such as those encountered by here. No aircraft would have withstood some of the landings in the MD-11 cases.

I am not saying the aircraft is not touchy and is most-likely caused by the smaller horizontal stab and resulting stability, but this is what is the cause of the resulting structural failures and the botched landings far beyond structural limits, not inherent structural flaws.

Quoting SEPilot (Reply 8):But no aircraft has EVER done it EXCEPT the MD-11, which has done it THREE times (out of only 200 built.)

Yes, I grant you that, but how is that a result of a supposed structural flaw and not the stability issues that lead to the botched landing beyond the flight envelope and structural limits? I don't understand how one can blame an aircraft for breaking up when its operated beyond its design limits. Its the result you are inciting, not the cause. I find it very difficult to accept that any other aircraft could have recovered in one piece from seeing video of the Narita crash and the forces induced. This was NOT a typical hard or bounced landing.

35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.

Quoting seabosdca (Reply 7):Also, it's at least conceivable that this problem is what caused UA 232, the Sioux City DC-10, to flip over.

I don't believe that is the case at all with the UA 232 crash, I'm pretty sure that it flipped because of the speed and the fact that it was not directly lined up with the runway so in a last second effort to correct the plane, the right wing lost enough lift to cause it to strike the ground first causing the flip over.

Quoting TZTriStar500 (Reply 9):I don't know where you get this from because you keep stating it like its fact. The DC-10/MD-11 gear is mounted aft of the rear spar just like the majority of all airliner designs. There is nothing inherently different about its design. All conventional MLG designs have the forward attachment to the rear spar and the aft to a MLG beam or aux spar. As seen in the images of the 757, 737NG, 767, and DC-10, I defy you to tell me where is the "flaw" or that Douglas did anything vastly different than convention.

Thanks TZ for that info, even though I've worked with most commercial aircraft I didn't know that. I will say the MD11 is a great plane too, when I was at FDX I know that the pilots really did like it and with the ability to also fly the MD10, most pilots that I met at ONTR preffered the MD11. My uncle used to fly the original two GE MD11's that DL had in 1990 and he said that it was a good airplane but was tricky beyond belief.

Of course not, but that's a very preferable outcome to a wing detaching.

Thanks for posting the diagrams above. They indicate my understanding of the DC-10/MD-11 wing structure was incorrect. The question I still have is why these violent landing events break wings off (leading to flips) on MD-11s and not on other types. That's a different question from why MD-11s suffer more violent landing events, which I think we agree on.

Quoting seabosdca (Reply 15):No one knows what happened in the SV case, but that description fits BA038 pretty well.

True, but I would hardly compare the MD-11 accidents to BA038, completely different accidents and circumstances.

Quoting seabosdca (Reply 15):The question I still have is why these violent landing events break wings off (leading to flips) on MD-11s and not on other types. That's a different question from why MD-11s suffer more violent landing events, which I think we agree on.

Simply because there hasn't been a string of violent landings with other types that lead to this. Again, its the result not the cause. There have certainly been accidents where wings have detached before with CO 1713 coming to mind. Though not similar at all to MD-11 accidents, to put it simply, if a wing contacts the ground first in a crash, its going to detach.

35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.

Quoting TZTriStar500 (Reply 16):to put it simply, if a wing contacts the ground first in a crash, its going to detach.

While I agree that; if the wing contacts the ground first something bad will happen, I think the term "its going to detach" is misleading. Becoming detached implies that it would fail at the attach point, where it mates with the fuselage/wing box. When in actuality the wing should fail at some point away from the attach point.

Quoting 474218 (Reply 17):While I agree that; if the wing contacts the ground first something bad will happen, I think the term "its going to detach" is misleading. Becoming detached implies that it would fail at the attach point, where it mates with the fuselage/wing box. When in actuality the wing should fail at some point away from the attach point.

Correct. Perhaps 'separate' or 'fail' is more descriptive of what would occur. I don't mean to imply the attachment point would fail by default.

On another note, I couldn't yet find my TriStar documents with a MLG attachment diagram as I wanted to show that as well in reply 9. I really wished I'd have saved at least an IPC, AMM, and SRM of the TriStar from ATA.

35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.

Quoting c5load (Reply 18):Pilots of KLM's MD-11s don't seem to have a problem. I haven't heard of any mishaps with that carrier. What about the recent rash of incidents with the 738? Is that a problem airplane too?

Did the 738 flip over? Has a 738 ever flipped over on landing? What was the cause of the 738 accidents? How many 73G-series aircraft have been built and how many accident reports have listed design flaws as contributing factors?

You're being deliberately obtuse to try to defend an indefensible point. It's well-known that the MD-11 has an issue with stability during difficult/windy landings. The Chinese air authorities have banned it from their airspace (not that I take the Chinese government's policies that seriously). Pilots have reported that it is more demanding than similar aircraft.

To brush these facts off as "paranoia" is not defensible. The MD-11 may not be "unsafe," but it isn't the best of designs.

Additionally, it underperformed and was designed with one engine too many. That's why there aren't many of them flying passengers around anymore. On the other hand, the 744, which was introduced prior to the MD-11, is still the backbone of many long-haul carriers. And the 744, unlike the MD-11, has never flipped over on a hard landing.

Quoting DocLightning (Reply 22):Additionally, it underperformed and was designed with one engine too many. That's why there aren't many of them flying passengers around anymore. On the other hand, the 744, which was introduced prior to the MD-11, is still the backbone of many long-haul carriers. And the 744, unlike the MD-11, has never flipped over on a hard landing.

It underperformed on its range/cost targets and was never sold as anything more than an updated DC-10 which it is. It was clearly not a clean-sheet design.

Why are you all so fixated on the fact that it flips over in a crash or violent landing exacerbated by its unforgiving stability issues that is arguably unrecoverable in any aircraft type? Shouldn't we be focused on why it gets to that effect? The MD-11 doesn't have problems because it flips over in a crash and flipping over does not cause it to crash, its a result.

Quoting United_fan (Reply 23):I did not know that there were only 11 pax MD-11's left. I thought Martinaire still have one . I guess they did not take into account the two Saudi VVIP M11's.

Actually there are approximately 22 pax aircraft left. KLM has 10, World has 6, 2 Saudi VVIP, and 4 stored (ex-Finnair).

35 years of American Trans Air/ATA Airlines, 1973-2008. A great little airline that will not be soon forgotten.

25 c5load
: If it is such a problem airplane, then why hasn't the FAA grounded all of them? If the crashes were directly attributed to design flaws, why hasn't t

26 ikramerica
: The question is: would another aircraft been in this situation in the first place? 1. Other aircraft have larger wings and horizontal stabs. 2. Other

27 FX1816
: Well that's just being ridiculous. Actually YOU were the one who brought up the 738 having recent issues.... FX1816

28 c5load
: What's so ridiculous about it? Obviously an airplane with design flaws that cause to flip when it crashes because of a hard landing should be immedia

29 tdscanuck
: It's not the MLG break that flips the airplane...that would just drop one side down on the nacelle (which has happened to lots of aircraft types). It

30 FX1816
: And do you really believe that the MD11 hasn't seriously been looked at by the FAA and other authorities from other countries??? I do like how you do

31 TZTriStar500
: Yes, I understand that, but to the MD-11 in particular, the center wing boxes themselves stayed intact and a wing separated outboard of that attachme

32 c5load
: Well, If YOU took the time to read the post to which I was responding to, then YOU would have seen that I was saying that no matter what the airplane

33 tdscanuck
: The principle applies to the whole wing, as you note, not just the center wing box. There's no real requirement that the wing box stay intact through

34 474218
: I did. However, the drawing does not do the MLG Trunnion Fitting justice. It is made from high strength steel and weighs 2000 lbs. The MLG Trunnion i

35 TZTriStar500
: Thanks for your input. I agree and not convinced what actually occurred as a result (post-crash) was due to any flawed structural design.

36 TZTriStar500
: Thanks Carl! It looks somewhat similar in configuration to the DC-10/MD-11 design and hope you don't take offense to that..haha

37 474218
: That's understandable, in the late 1960's I think there were engineers that worked day shift at Lockheed and swing shift at McD. I know I worked for

38 FX1816
: I'm not trying to start an argument either but UPS HAS had a landing incident with the MD11: UPS MD11 nose gear collapse http://ntsb.gov/ntsb/brief.a